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pitting in aluminum weld

09-16-2013, 04:41 PM

Hello, I have been having a few issues with aluminum lately, the worst being pitting in the weld, that has been driving me nuts. All of these issues only happen with a newer welder that I bought. THe welder in question is a 250 Snycrowave (sn# lg480049l). T weld looks ok on the outside, a little grainy and dull, but the bead is filled will gas pockets that only come out when ground down. Material is 6061 or cast mold plate, I am using both 4043 and 5056 and have the same issues. thicknesses vary from 1/4 to up to 4" thick. some times I pre heat sometimes not. I have tried pure, thoriated and ceriated and have the same issues. I like to weld hot, but very my amps as needed with the pedal. Filler and base materials cleaned with acetone and SS brush or scotch brite pad. Attached is a picture of the pitting.

I will try to make a sample tomorrow with more accurate info for amperage, material, cleaning, rod, ect with a before and after grinding.

Comment

THe welder, is not in a area where there is air flow, I have no issues with contamination welding steel/stainless. I have tried multiple CFH for 12 to 20. I suppose it could be a gas issue, but I have never been able to make this machine weld like my older 250 snyc. I have never had pitting, but the weld has been grainy and dull, no matter what I do with ac balance and filler.

Comment

THe welder, is not in a area where there is air flow, I have no issues with contamination welding steel/stainless. I have tried multiple CFH for 12 to 20. I suppose it could be a gas issue, but I have never been able to make this machine weld like my older 250 snyc. I have never had pitting, but the weld has been grainy and dull, no matter what I do with ac balance and filler.

Porosity in aluminum is caused by one thing and one thing only: Hydrogen.

There are many causes for the trapped hydrogen but the machine is not one of them. Neither is the type of tungsten used.

Comment

I just did a little bit of goggleing, and it says that hydrogen comes from water vapor or grease. In the case of the mold plate it was definitely hot, especially by the time I got through half of it. I cleaned both the mold and rod with SS brush/scotch brite and acetone. The only place grease could be coming from is my gloves, which some times handle dirty steel. Generally I like to have two pairs of gloves, but am running on one pair now.

While I am not blaming these issues on the welder I have never been able to make it produce satisfactory aluminum welds.

attached are some recent welds that are also grainy and dull, but dont have the porosity issues (material is 1/4 x 2 6061)

Comment

I just did a little bit of goggleing, and it says that hydrogen comes from water vapor or grease. In the case of the mold plate it was definitely hot, especially by the time I got through half of it. I cleaned both the mold and rod with SS brush/scotch brite and acetone. The only place grease could be coming from is my gloves, which some times handle dirty steel. Generally I like to have two pairs of gloves, but am running on one pair now.

While I am not blaming these issues on the welder I have never been able to make it produce satisfactory aluminum welds.

attached are some recent welds that are also grainy and dull, but dont have the porosity issues (material is 1/4 x 2 6061)

The pic you posted shows contamination in the bead. That is the "pepper" looking specs and the black soot at the start of the bead.

Hydrogen can come from" just about" anything that isn't aluminum, argon or helium. Not just grease or water vapor.

Comment

Hello, I have been having a few issues with aluminum lately, the worst being pitting in the weld, that has been driving me nuts. All of these issues only happen with a newer welder that I bought. THe welder in question is a 250 Snycrowave (sn# lg480049l). T weld looks ok on the outside, a little grainy and dull, but the bead is filled will gas pockets that only come out when ground down. ........

1-If you're watching the puddle in action--normally one can see porosity forming, bubbling, coming up thru and around the puddle.

2-The cast mold plate pic you posted looks like classic--just below the parent mold surface--fine, casting porosity--inherent to the casting.
In 'normal' AL castings--porosity is ever present. (High end, investment castings have limited to zip porosity.) Trying to boil out and fill myriad, scattered casting subsurface porosity is an exercise in futility.....if the goal is zero porosity after machining.

3-If you're getting porosity on wrought AL, then it's time to consider the usual suspects.

4-Grabbing whatever type of filler rod to weld whatever type of AL
can create other problems you don't need. Suggest studying what Alcotech recommends--despite the recco's of board pundits.